A nuclear-armed North Korea poses the real danger to the world including its allies China and Russia, US National Security Advisor Lieutenant General H R McMaster said today.

Pyongyang acquiring nuclear weapons "would be the most destabilising development" in the post-World War II period, he told Fox News.

"It is something that places us at direct risk, but places the world at risk. This is a regime that's never met a weapon that it hasn't proliferated. It's a regime who's said clearly its intentions are to use that weapon for nuclear blackmail and then to quote, "reunify" the peninsula under the red banner," McMaster said.

"So he would use this to get -- extract payoffs, as the regime has done with their nuclear program in the past, and to drive the States and our allies away from this peninsula that he would then try to dominate. And if you want to know what life looks like under a North Korea regime, you just have to look north of the 38th parallel," he said.

McMaster said the other grave concern is that he would proliferate or sell off these weapons to others.

"And there's never been a weapons system that North Korea has developed that it hasn't sold to somebody else," he said.

The NSA said that there's a real grave danger to China, Russia, to all nations, from a North Korea that's armed with nuclear weapons.

"You have that direct threat, but you also have the threat the potential of Japan, South Korea, others, arming themselves, possibly even with nuclear weapons. That is not in China's interest; it's not in Russia's interest," he said.

President Donald Trump has said that the US will have to take care of it, because he has said he's not going to allow this murderous, rogue regime to threaten the US with the most destructive weapons on the planet, McMaster said.

Asked if he was in contact with other countries to reassure them that Trump was firmly in charge and his presidency was not in trouble, he said: "No, I don't think our allies need any reassurance.

"In fact, what we're doing is continuing to work with them on all the key challenges we face today, from North Korea, to the defeat of ISIS across the Greater Middle East, the ongoing efforts in Afghanistan, Pakistan".

"We're working with our Latin American partners very closely on the issue of Venezuela. And so, we haven't missed a beat, really, and the topic doesn't even come up," the top national security advisor to the US president said.

The investigations related to his predecessor General (retired) Michael Flynn is not the focus on the National Security Council.

"What we're focused on are, the key issues that we have to confront today to protect the American people, advanced our prosperity.

"The priorities that the president's given us to move as quickly as we can to resolve this crisis with North Korea, a regime that's threatening the world, and to do everything we can to, as we defeat ISIS in the greater Middle East, make sure conditions are set so that ISIS doesn't return," he said.

They also address the problem of Iranian influence across the region, which is driving a lot of this humanitarian and political crisis in the Middle East, McMaster said.

Responding to a question on news reports of replacing Rex Tillerson as the Secretary of State, he said that he is not aware of any such plan.

"I'm not aware of any plan at all. What I'm aware of is that the secretary of state is travelling today to advance and protect our interests, as is our secretary of defence," McMaster said, adding that they met on some very important topics in the past week, and have brought some great options to the president to protect the American people, and advance their interests where those interests are at risk.

"So, the national security team, again, is not missing a beat, and I think is doing what the president expects of us, and what the American people expect of us," he added.

(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)